Image forming apparatus

Abstract

The present invention provides an image forming apparatus that can suppress the decrease in the efficiency of paper dust collection. [Solution] One of the holding portion and the gripping portion has a cylindrical outer cylinder portion extending from its axial end to the other side of the holding portion and the gripping portion. The other of the holding portion and the gripping portion has a cylindrical inner cylinder portion extending from its axial end to the one side of the holding portion and the gripping portion and positioned inside the outer cylinder portion. The holding portion is connected to the gripping portion so as to be able to swing in the axial direction via an elastic member positioned inside the inner cylinder portion. The outer cylinder portion has an opening that penetrates radially. The inner cylinder portion has a projection that protrudes from its outer circumferential surface and is positioned inside the opening. When the holding portion swings, the projection moves axially inside the opening.

Description

Technical Field

[0001] The present invention relates to an image forming apparatus including a pair of rollers for transporting paper and a paper dust collecting member for collecting paper dust adhering to the pair of rollers.

Background Art

[0002] A conventional image forming apparatus includes a pair of rollers and a paper dust collecting member. The pair of rollers is disposed in the apparatus main body and nips and transports paper. The paper dust collecting member is movable in an insertion / removal direction along the axial direction of the pair of rollers and is disposed in contact with one of the rollers of the pair of rollers to collect paper dust adhering to the pair of rollers.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the configuration of Patent Document 1, when the pair of rollers slides in the axial direction, the contact position between the paper dust collecting member and the roller may shift, resulting in a possible decrease in the paper dust collection efficiency.

[0005] In view of the above problems, an object of the present invention is to provide an image forming apparatus capable of suppressing a decrease in the paper dust collection efficiency. [[ID=SenteceNo=41]]

Means for Solving the Problems

[0006] To achieve the above objective, the first configuration of the present invention provides an image forming apparatus comprising a pair of rollers and a paper dust collection member. The pair of rollers is arranged on the main body of the apparatus and nips and transports paper. The paper dust collection member is movable in and out along the axial direction of the pair of rollers and is positioned in contact with one of the rollers of the pair to collect paper dust adhering to the pair of rollers. The paper dust collection member comprises a contact member and a holding member. The contact member contacts the pair of rollers to collect paper dust. The holding member holds the contact member. The holding member comprises a holding portion and a gripping portion. The holding portion extends axially and holds the contact member. The gripping portion is positioned on one side of the holding portion in the axial direction. One of the holding portion and the gripping portion has a cylindrical outer cylinder portion extending from its axial end to the other side of the holding portion and the gripping portion. The other of the holding portion and the gripping portion has a cylindrical inner cylinder portion extending from its axial end to the one side of the holding portion and the gripping portion and positioned inside the outer cylinder portion. The holding portion is connected to the gripping portion so as to be able to swing in the axial direction via an elastic member located inside the inner cylinder portion. The outer cylinder portion has an opening that penetrates radially. The inner cylinder portion has a projection that protrudes from its outer circumferential surface and is located inside the opening. When the holding portion swings, the projection moves axially inside the opening. [Effects of the Invention]

[0007] According to the first configuration of the present invention, it is possible to provide an image forming apparatus that can suppress a decrease in the efficiency of paper dust collection. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic cross-sectional view showing the structure of an image forming apparatus according to one embodiment of the present invention. [Figure 2] This is a cross-sectional view showing a pair of resist rollers and a paper dust collection member of an image forming apparatus according to one embodiment of the present invention, viewed from the axial direction. [Figure 3] This is a perspective view of a paper dust collection member of an image forming apparatus according to one embodiment of the present invention. [Figure 4] This is a cross-sectional perspective view showing a portion of the paper dust collection member of an image forming apparatus according to one embodiment of the present invention. [Modes for carrying out the invention]

[0009] Embodiments of the present invention will be described below with reference to the drawings. Figure 1 is a schematic cross-sectional view showing the structure of an image forming apparatus 100 according to the first embodiment of the present invention. For convenience of explanation, the vertical direction is defined as the up-down direction (Z1-Z2) when the image forming apparatus 100 is in a usable installation state (as shown in Figure 1). The front-to-back direction (Y1-Y2) is defined with the front side of the image forming apparatus 100 shown in Figure 1 as the front. The left-to-right direction (X1-X2) is defined with reference to the front of the image forming apparatus 100 in its installed state. In this embodiment, the left-to-right direction (X1-X2) is orthogonal to the up-to-down direction (Z1-Z2) and the front-to-back direction (Y1-Y2). The left-to-right direction (X1-X2) is defined as the opposing direction of the pair of sides of the image forming apparatus 100, and the front-to-back direction (Y1-Y2) is defined as the axial direction of the pair of registration rollers 13. Note that this definition of the up-to-down direction does not limit the orientation and positional relationship of the image forming apparatus 100 when it is in use.

[0010] The image forming apparatus 100 comprises an image forming section Pa to Pd, a paper feeding unit 60, a transfer section 50, a fixing section 14, an discharge section 17, a transport roller pair 40, a paper transport path 19, and a branch transport path 30.

[0011] The image forming apparatus 100 (in this case, a color printer) has four image forming units Pa, Pb, Pc, and Pd arranged in order from the upstream side in the transport direction (left side in Figure 1). The image forming units Pa to Pd form an image on the paper (recording medium) P.

[0012] More specifically, the image forming sections Pa to Pd are provided to correspond to images of four different colors (yellow, cyan, magenta, and black). The image forming sections Pa to Pd sequentially form images of yellow, cyan, magenta, and black through the processes of charging, exposure, development, and transfer, respectively.

[0013] The image forming sections Pa to Pd form visible images (toner images) of each color on the photoreceptor drums (image carriers) 1a to 1d. In addition, an intermediate transfer belt (intermediate transfer body) 8, which rotates counterclockwise in Figure 1, is provided adjacent to each image forming section Pa to Pd. The toner images formed on the photoreceptor drums 1a to 1d are sequentially transferred and superimposed onto the intermediate transfer belt 8, which moves while in contact with each photoreceptor drum 1a to 1d.

[0014] The transfer unit 50 transfers the toner image formed in the image forming units Pa to Pd onto the paper P (recording medium). The transfer unit 50 includes a drive roller 11 and a secondary transfer roller 9. Specifically, the toner image that has been primary transferred onto the intermediate transfer belt 8 is secondary transferred onto the paper P, which is an example of a recording medium, by the secondary transfer roller 9. Furthermore, the paper P on which the toner image has been secondary transferred is discharged from the main body of the image forming apparatus 100 after the toner image has been fixed in the fixing unit 14.

[0015] The paper feeding unit 60 supplies paper P to the image forming units Pa to Pd. Specifically, the paper feeding unit 60 has a pickup roller 62, a feed roller 63a, and a retard roller 63b. The paper feeding unit 60 is located above the paper cassette 61 Z1. The paper cassette 61 is located at the bottom of the main body of the image forming apparatus 100 and contains the paper P on which the toner image is secondarily transferred.

[0016] The pickup roller 62 presses against the upper surface of the paper P with a predetermined pressure. The feeding of the paper P is started by rotating the pickup roller 62. That is, the pickup roller 62 contacts the paper (recording medium) P contained in the paper cassette 61 and feeds the paper (recording medium) P into the paper transport path 19.

[0017] The feed roller 63a and the retard roller 63b constitute the feed roller pair 63. The feed roller 63a conveys the paper (recording medium) P sent out by the pickup roller. Also, the retard roller 63b is pressed against the feed roller 63a to form a nip portion, and conveys the paper (recording medium) P while sorting it out.

[0018] A sheet made of a dielectric resin is used for the intermediate transfer belt 8, and a seamless belt is mainly used. Also, a blade-shaped belt cleaner 25 for removing toner and the like remaining on the surface of the intermediate transfer belt 8 is disposed on the downstream side of the secondary transfer roller 9.

[0019] Around and below the rotatably arranged photosensitive drums 1a to 1d, charging devices 2a, 2b, 2c and 2d, an exposure device 5, developing devices 3a, 3b, 3c and 3d, and cleaning devices 7a, 7b, 7c and 7d are provided. The charging devices 2a, 2b, 2c and 2d charge the photosensitive drums 1a to 1d. The exposure device 5 exposes the photosensitive drums 1a to 1d with image information. The developing devices 3a, 3b, 3c and 3d form toner images on the photosensitive drums 1a to 1d. The cleaning devices 7a, 7b, 7c and 7d remove the developer (toner) and the like remaining on the photosensitive drums 1a to 1d.

[0020] When image data is input from a host device such as a personal computer, first, the charging devices 2a to 2d uniformly charge the surfaces of the photosensitive drums 1a to 1d. Next, light irradiation is performed according to the image data by the exposure device 5 to form an electrostatic latent image corresponding to the image data on each of the photosensitive drums 1a to 1d. The developing devices 3a to 3d are each filled with a prescribed amount of a two-component developer containing yellow, cyan, magenta, and black toner. When the ratio of the toner in the two-component developer filled in each of the developing devices 3a to 3d falls below a prescribed value due to the formation of the toner image, toner is replenished from the toner containers 4a to 4d to each of the developing devices 3a to 3d.

[0021] The toner in the developer is supplied onto the photoreceptor drums 1a to 1d by the developing devices 3a to 3d and adheres electrostatically. Thereby, a toner image corresponding to the electrostatic latent image formed by the exposure from the exposure device 5 is formed.

[0022] Then, an electric field is applied at a predetermined transfer voltage between the primary transfer rollers 6a to 6d and the photoreceptor drums 1a to 1d by the primary transfer rollers 6a to 6d, and the yellow, cyan, magenta, and black toner images on the photoreceptor drums 1a to 1d are primarily transferred onto the intermediate transfer belt 8. These images are formed with a predetermined positional relationship. Thereafter, in preparation for the formation of a new electrostatic latent image that is subsequently performed, toner and the like remaining on the surfaces of the photoreceptor drums 1a to 1d after the primary transfer are removed by the cleaning devices 7a to 7d.

[0023] The intermediate transfer belt 8 is stretched between the upstream driven roller 10 and the downstream drive roller 11. When the intermediate transfer belt 8 starts to rotate counterclockwise as the drive roller 11 rotates by a belt drive motor (not shown), the sheet P is conveyed from the registration roller pair 13 to the secondary transfer nip portion N between the drive roller 11 and the secondary transfer roller 9 provided adjacent thereto at a predetermined timing. Then, the toner image on the intermediate transfer belt 8 is secondarily transferred onto the sheet P passing through the secondary transfer nip portion N.

[0024] The sheet P having the toner image secondarily transferred thereon is conveyed to the fixing unit 14. The fixing unit 14 has a fixing belt 14a and a pressure roller 14b. The fixing belt 14a is heated by a heating device (not shown) such as a heater or an induction heating unit. The pressure roller 14b is pressed against the fixing belt 14a to form a fixing nip and applies a rotational driving force to the fixing belt 14a.

[0025] The sheet P conveyed to the fixing unit 14 is heated and pressed by the fixing belt 14a and the pressure roller 14b, and the toner image is fixed on the surface of the sheet P, and a predetermined full-color image is formed.

[0026] The paper P on which the full-color image has been formed is directed in a different direction by a transport guide member 15 located at the branching point of the paper transport path 19, after passing through a transport roller pair 40. It is then discharged into the discharge tray 18 by a discharge roller pair (discharge section) 17 (or after being sent to the branching transport path 30 where images are formed on both sides).

[0027] The transport roller pair 40 feeds the paper (recording medium) P from the fixing unit 14 to the discharge roller pair (discharge unit) 17.

[0028] The paper transport path 19 connects the paper feeding section 60, the transfer section 50, the fixing section 14, and the discharge section 17. The branch transport path 30 branches off from the paper transport path 19 downstream of the transport roller pair 40 and communicates with the paper transport path 19 upstream of the registration roller pair 13. The branch transport path 30 extends vertically (Z1-Z2) along the side surface 102 of the image forming apparatus 100 and is curved in a roughly C-shape.

[0029] Figure 2 is a cross-sectional view showing the resist roller pair 13 and the paper dust collection member 20 viewed from the axial direction, and Figure 3 is a perspective view of the paper dust collection member 20. Figure 4 is an enlarged cross-sectional perspective view showing a part of the paper dust collection member 20. The resist roller pair 13 is composed of a metal roller, for example made of iron, which is the driving roller, and a rubber roller, which is the driven roller. The two rollers are arranged parallel to each other and pressed together to form a nip section. The resist roller pair 13 corrects the skewness of the paper P by bringing the leading edge of the paper P into contact with the nip section. The resist roller pair 13 is also rotated by a drive motor (not shown) to transport the paper P to the secondary transfer nip section N in accordance with the image formation timing.

[0030] A paper dust collection member 20 is provided near the resist roller pair 13. The paper dust collection member 20 extends axially along the resist roller pair 13 and is movable in and out along the axial direction of the resist roller pair 13 (hereinafter referred to as the axial direction) on a rail (not shown). The paper dust collection member 20 is positioned in contact with the circumferential surface of one of the rollers of the resist roller pair 13 to collect paper dust adhering to the resist roller pair 13.

[0031] The paper dust collection member 20 includes a contact member 21 and a holding member 22. The contact member 21 contacts one of the resist roller pair 13 (for example, a metal roller, the left roller in Figure 2) to collect paper dust and is made of, for example, a sponge.

[0032] The holding member 22 holds the contact member 21 and is made of resin. The contact member 21 is formed in a rectangular parallelepiped shape extending in the axial direction and is adhesively fixed to the holding member 22. The upper surface 21a of the contact member 21 is a collection surface that contacts the resist roller pair 13 to collect paper dust.

[0033] The holding member 22 has a holding portion 221 and a gripping portion 222. The holding portion 221 extends axially and holds the contact member 21. The gripping portion 222 is positioned Y1 in the withdrawal direction (one side in the axial direction) of the holding portion 221 and is gripped by the fingers when inserting and removing the paper dust collection member 20.

[0034] The retaining portion 221 has a cylindrical outer cylinder portion 2211. The outer cylinder portion 2211 extends in the withdrawal direction Y1 from the end of the retaining portion 221 in the withdrawal direction (axial direction) Y1. In this embodiment, the retaining portion 221 and the outer cylinder portion 2211 are integrally molded from resin. The outer cylinder portion 2211 has an opening 2211a that penetrates radially and extends axially.

[0035] The gripping portion 222 has an inner cylindrical portion 2221. The inner cylindrical portion 2221 extends in the insertion direction (axial direction) Y2 from its end in the insertion direction (axial direction) Y2 and is positioned inside the outer cylindrical portion 2211. In this embodiment, the gripping portion 222 and the inner cylindrical portion 2221 are integrally molded from resin. The inner cylindrical portion 2221 has a protruding portion 2221a that protrudes from its outer circumferential surface and is positioned inside the opening 2211a.

[0036] The protrusions 2221a are located at two locations on the upper and lower parts of the inner cylinder 2221. The openings 2211a are also located at two locations on the upper and lower parts of the outer cylinder 2211, corresponding to the protrusions 2221a. In other words, multiple protrusions 2221a are arranged circumferentially on the outer surface of the inner cylinder 2221, and multiple openings 2211a are arranged corresponding to each of the protrusions 2221a.

[0037] A coil spring (elastic member) 223 is arranged inside the inner cylinder portion 2221. In this embodiment, the end of the coil spring 223 in the insertion direction (the other axial direction) Y2 is fixed to the bottom of the outer cylinder portion 2211. As a result, the holding portion 221 is connected to the gripping portion 222 via the coil spring (elastic member) so that it can swing in the axial direction (Y1-Y2). This allows the contact member 21 to follow axially if one of the resist roller pair 13 that contacts the paper dust collection member 20 is displaced in the axial direction (Y1-Y2). Therefore, a decrease in the efficiency of paper dust collection can be suppressed.

[0038] When the holding portion 221 swings, the protruding portion 2221a moves axially within the opening 2211a. This guides the protruding portion 2221a within the opening 2211a, allowing the holding portion 221 to swing smoothly in the axial direction. In this case, if multiple protruding portions 2221a and openings 2211a are arranged, the holding portion 221 swings more smoothly in the axial direction.

[0039] Furthermore, the axial swing range of the holding portion 221 is restricted by the axial width of the opening 2211a. Also, if the holding portion 221 swings significantly relative to the gripping portion 222, the protruding portion 2221a will come into contact with the periphery of the opening 2211a. This prevents the gripping portion 222 from coming out of the holding portion 221 in the withdrawal direction Y1 when the paper dust collection member 20 is removed from the main body of the image forming apparatus 100.

[0040] Furthermore, the tip of the projection 2221a is bent in the axial direction Y1, and the opening 2211a has an inclined surface 2211b. The inclined surface 2211b is inclined in the withdrawal direction Y1 (the direction in which the projection 2221a bends) as the peripheral edge of the opening 2211a moves upward (radially outward). In addition, in this embodiment, the tip of the projection 2221a has an opposing surface 2221b that faces the inclined surface 2211b in the axial direction and is inclined at the same angle as the inclined surface 2211b.

[0041] As a result, when a large force is applied to the gripping portion 222 in a direction that moves it away from the holding portion 221 against the biasing force of the coil spring 223, the opposing surface 2221b of the protrusion 2221a comes into contact with the inclined surface 2211b, and the protrusion 2221a is hooked onto the periphery of the opening 2211a. This makes it possible to more reliably prevent the gripping portion 222 from coming out of the holding portion 221 in the withdrawal direction Y1.

[0042] It should be noted that the embodiments disclosed herein are illustrative and not restrictive in all respects. The scope of the present invention is indicated by the claims rather than by the description of the embodiments above, and further includes all modifications within the meaning and scope equivalent to the claims.

[0043] For example, an example of applying the present invention to a monochrome printer has been shown, but the present invention is not limited to this. Needless to say, the present invention can be applied to various image forming devices such as color printers, monochrome copiers, digital multifunction printers, and facsimile machines, which are equipped with a pair of rollers for transporting paper and a paper dust collection member for collecting paper dust adhering to the pair of rollers.

[0044] Furthermore, although the above embodiment shows an example in which paper dust adhering to a pair of resist rollers is collected, the present invention is not limited to this, and may be configured to collect paper dust adhering to a pair of rollers other than a pair of resist rollers.

[0045] Furthermore, in the above embodiment, the outer cylinder portion 2211 is provided on the holding portion 221 and the inner cylinder portion 2221 is provided on the gripping portion 222. However, the inner cylinder portion 2221 may be provided on the holding portion 221 and the outer cylinder portion 2211 may be provided on the gripping portion 222. In this case, it is preferable that the tip of the protruding portion 2221a is bent in the axial direction Y2. [Explanation of Symbols]

[0046] 1a~1d Photoconductor drum 2a~2d Charging device 3a~3d developing device 4a~4d Toner container 5. Exposure apparatus 6a~6d Primary transfer roller 7a~7d Cleaning equipment 8. Intermediate transfer belt 9. Secondary transfer roller 10 Driven rollers 11 Drive rollers 13 Resist Roller vs 14 Fixing section 14a Fixing belt 14b Pressure Roller 15 Conveyor guide member 17 Discharge section 18 Output tray 19. Paper transport path 20 Paper dust collection member 21 Contact Member 21a Top surface 22 Retaining member 25 Belt Cleaner 40 Conveyor Rollers 50 Transfer section 60 Paper feed section 60 Paper feed unit 61 Paper Cassette 62 Pickup Roller 63 Feeding roller pair 63a Feed Roller 63b Retard Roller 100 Image forming apparatus 102 Side view 221 Holding part 222 Gripping part 223 Coil spring 2211 Outer cylinder 2211a opening 2211b Slope 2221 Inner cylinder 2221a Protrusion 2221b Opposite side N Secondary transfer nip section P paper Pa~Pd Image Forming Unit Y1 Extraction direction Y2 Insertion direction

Claims

1. The device is equipped with a pair of rollers that nip and transport the paper, The system includes a paper dust collection member that is movable in the axial direction of the roller pair and is positioned in contact with one of the rollers of the roller pair to collect paper dust adhering to the roller pair, The paper dust collection member comprises a contact member that contacts the roller pair to collect the paper dust, and a holding member that holds the contact member. The aforementioned retaining member is A holding portion that extends in the axial direction and holds the contact member, It has a gripping portion positioned on one side in the axial direction of the holding portion, One of the holding portion and the gripping portion has a cylindrical outer cylinder portion extending from the axial end to the other side of the holding portion and the gripping portion. The other of the holding portion and the gripping portion has a cylindrical inner cylinder portion that extends from the axial end to one side of the holding portion and the gripping portion and is disposed inside the outer cylinder portion. The holding portion is connected to the gripping portion so as to be able to swing in the axial direction via an elastic member disposed inside the inner cylinder portion. The outer cylinder portion has an opening that penetrates in the radial direction, The inner cylinder portion has a protruding portion that extends from the outer surface and is positioned inside the opening. An image forming apparatus wherein, when the holding portion swings, the protruding portion moves axially within the opening.

2. The aforementioned protrusion has a tip that is bent in the axial direction. The image forming apparatus according to claim 1, wherein the opening has an inclined surface that slopes in the direction of the bending of the protrusion as the peripheral edge extends radially outward.

3. The image forming apparatus according to claim 2, wherein the tip of the protruding portion has an opposing surface facing the inclined surface in the axial direction, and the opposing surface facing the inclined surface is inclined at the same angle as the inclined surface.

4. The aforementioned protrusions are arranged in multiple circumferential directions on the outer surface of the inner cylinder portion. The image forming apparatus according to claim 1 or claim 2, wherein a plurality of the openings are arranged corresponding to each of the protruding portions.

5. The image forming apparatus according to claim 1 or 2, characterized in that the roller pair is a pair of registration rollers that correct the skewness of the paper and transport the paper to the image forming unit in accordance with the image forming timing.

Images